DESCRIPTION: (Adapted From The Applicant's Abstract.) PI Medical (PIM) and the University of Washington (UW) propose jointly to design, fabricate and test two new, unique multi-electrode arrays for cochlear implants. The arrays are designed to be implanted in the scalae tympani of profoundly deaf human patients. Improved function of the arrays will be obtained using novel design and fabrication techniques pioneered by PIM. The fundamental design strategy will be based on the research experience of the team at UW. The collaboration should provide the medical community with substantially improved functionality of the electrode arrays at a significantly lower cost than the arrays in use today. Using precise anatomicalgeometries of the cochlea obtained by the UW group, arrays will be designed to optimize contact placements near neural elements and increase the depth of surgical implantation into the scala tympani. Contact counts will be increased by at least a factor of two over the 22-electrode arrays that are presently used commercially. The electrode geometry and placement will permit finely focused stimulation of auditory nerve cells. The electrodes reproducibility will be improved and costs reduced by use of micromachining and thin-film techniques. We anticipate that profoundly deaf patients with remaining VIII nerve cells will have improved speech discrimination over those patients who use existing devices.